Understanding modulated structures in Heusler alloys

Modulated structures play often a prominent role in functional materials. In particular in Heusler Ni-Mn-Ga magnetic shape memory alloys it seems that it is the modulation, what gives the materials the unique properties. The nature of the modulation in martensite phases is disputed, varying between harmonic commensurate modulation to nanotwinned, hierarchical structures. The division can be partly artificial, as suggested by recent theoretical results and experiments, both made by members of project team. The proposed project is built on these recent findings. We will investigate the origin of the modulation and the way of the formation of modulated phases and changes between different kinds of modulations by combination of mathematical modelling and dedicated experiments to probe structural, magnetic, (magneto-)elastic and transport properties. Although the focus will be on Ni-Mn-Ga, we will prepare new alloys and single crystals to have a comparison for modulation in different materials.